my special needs son needs his passwords reset but we can't remember password to iCloud.com account or his verification questions

For the email account, go to the email provider's website, and in the log in area, there should be a Forgot Password option.

For the security questions, if you are being told there isn't enough information to reset them, contact Apple ID Support.

If you don't know the answers, if the steps in the article below don’t work, contact Apple ID Support, although based on multiple posts I have read, they will not help you recover the answers to your security questions.

 Apple ID - If you forgot the answers to your Apple ID security questions.      *

From the article below. 

Without proof of your identity via security questions and other carefully selected criteria, Apple Support can't help you reset a password or perform any other actions on your account. These policies are audited and reviewed on a regular basis.

Security and your Apple ID.    *

Apple ID - Official Apple Support.    -

Contact Apple for help with Apple ID account security - Apple Support.  * (Link doesn't always load)  

Get Support   - Work through the screens to get a chat option. 

Apple Support schedule phone call. -

Apple on Twitter

Messages chat with Apple

If you forgot the Apple ID (iCloud) password, enter the Apple (iCloud) ID, and click Forgot Password. See if you can get a Rescue or Notification email option if necessary. Link to contact Apple Support at the end of the 2nd article.

Apple ID - Manage

Apple ID – Forgot Password  *      

Try the steps for the Account Recovery process first:

How to use account recovery when you can’t reset your Apple ID password - Apple Support

Apps are tied to the Apple ID that has been used to download them. If you create a completely new Apple ID, you can't merge those two Apple ID accounts.